Tube-mill.



P. T. LINDHARD.

TUBE MILL. APPLmATmN FILED JMJ. 1910.

Patented Jan. 31, 1911.

immuun y.

EMM/imm@ UNITED strates PVL T. LINDHARD, OF NEW YORK, N. Y.,

OFFICE.

ASSIGNOR TO F. L. SMIDTH @L -C0., 0F NEW YORK, N. Y., A CORPORATION OF NEW JERSEY.

TUBE-MILL.

Specification of Letters Patent.

Patented J an. 31, 1911.

Application fled. January 5, 19113. Serial No. 536,448.

To all whom it may concern:

Be it known that I, PovL T. LiNnHAnD, a subject of the King of Denmark, residing in the borough of Manhattan of thecity of New York, in the State of New York, have invented certain new and useful Improve ments in Tube-Mills, of which the following is specilication, reference being had to the accompanying drawing` forming a part hereof.

This invention relates to rotary mills in which coal or any other substance to be pulverized is iirssubjected to the action of relatively large grinding bodies and then passed through a perforated partition into another compartment in which the partly pulverizcd material is subjected to the action of small cylindrical grinding bodies. In order that the openings through the partition shall not become clogged by the partly pulverized material, such openings are made to Hare toward the second compartment and, being usually formed as long slots in the partition, so that ample space may be afforded for the passage of the partly pulverized material, it is found that the small, cylindrical grinding bodies used in the se@ ond compartment, having a diameter less than the maximum width of the slots, so1netimes lodge in the slots with their axes pan allel with the plane of the partition, thereby clogging the openings and restricting the free passage ofthe partly pulverized material. therethrough.

It is the object of this invention to so -form the openings4 through the partition that the small cylindrical grinding bodies cannot lodge in such openings with their axes parallel with the plane f the partition and wherein each slot through the partition, although having a total continuous length many times the length of a small, cylindrical grinding body and flaring toward the second compartment so as to permit clear ance of the partly pnlverized material, is formed with bearing points separated by less than the length of a. grinding body, so that the grinding bodies cannot lodge in the slots with their axes parallel with the 'plane of the partition. They may lodge with opg. end in the slot and the other projecting into the compartment, but ifthey do so lodge they vvill` be dislodggi quickly by the striking of the projecting 'ds by other grinding bodies in the second compartment. It will be obvious that the slots may be formed in many different ways in order to secure the desired result and in the drawing several different forms are illustrated.

In the draWingWFigure l is a view in longitudinal section of a tubcnnill which einbodies the invention. l? ig. is a detail View,

on a larger scale, of the partition as seen from the right hand in Fig'. l. Fig. 3 is a detail view in section on the plane indicated by the line 3M?. of Fig. 2. Figs. 4, 5 vand (5 are detail views showing different forms which may be given to theslotsin accordance with the invention.

The tubemill may hc constructed in any suitable manner. As shown in Fig. l of the drawing, it comprises the usual cylindrical shell a with a feed head Z) and discharge head c. Usually such a mill has but a single grinding chamber, in which are placed the grinding bodies which are usually comparatively large lint pebbles. It has been found, hou'ever, that much better results can be secured if thc material to be pulverized is first subjected to the action of the llint pebbles, indicated at al, in a relatively large eompartn ment e, and the partly pulvcriaed material passes innnediately .from lhe compartment e, through a. perforated partition j', into 'a smaller compartment g, iu which it is subjected to the action of comparatively small, cylindrical grinding bodies /t of metal, the pulverized material linally passing out of the shell a through the discharge head of In order hat the partly pulver-ized material may pass freely from thc compartmente to the compartment g', it has been found desii-able to form in the partition f numerous long slots which flare outwardly toward-the 'compartment g1- It has also been found, however, that if .the slots are simple straight slots, exceeding in length the length of the grinding bodies h, it frequently happens that the grinding bodies 7L, the diameter of Which is less-than the maximum width of the slots, lodge in the slots with their parallel axes with the plane of the plate, thereby, to that extent, clogging the slots and preventing the free passage of the partly pulverized material. i

In accordance with this invention, the slots f in the partition plate f have each a lengthv considerably greater than the length a grinding body.

of a grindingA body and are flared toward the compartment g, but each continuous long slot is formed With bearing points Whlch are se Jarated b a distance less than the length oi one of tie grinding bodies 71 so that a grinding body cannot lodge in a slot With its axis parallel with the plane ot the plate, but ifit lodges in the slot at one end7 shall have its other end beyond the face of the plate so that it shall be struck by other grinding bodies in the compartment g and shall be dislodged. lt will be obvious that the slots may be so formed as to provide the necessary bearing` points in many different Ways. Preferably nach slot is zigzag, either on straight lines, as shown in 2 and 5, or on straiglitvlines as shown at j" in Fig'. 3, and'at fi in Fig. 5, or on curved lines as shown at f in Fig. G. lit the continuons slot f' is formed, as shown in Figs. and il. ot Short staggered .sections'7 the points f forni bearing points which are separated longitin dii'ially by a distance than the length of a grinding body Iii, and are separated laterally by a distance less than the diameter ot Such grinding body, so that it is inipossible for a grindinl body to lodge in the slot With its axis parallel with the plane ot the plate, while neither the etl'eetiro area of the slot nor the flaring necessary-Y to gire elearance is reduced. lt' the slot be zigzagwith straight lines. as shown` at f3 in Fig. '5, or With curved lines. as shown at j" in Fig. t3, bearing points are 'formed at ff'. and f5 in Fig. 5 and at j'0 and ,fw in Fig. t, which i are separated by than the lcnoth oi' a grinding body it so that it is impossible .tor such grinding body to lie in the slot with its axis parallel With the plane ot the plate. Preferably, each slot` although Continuons. is zigzag/in one Way or another, as indicated in Figs, f2, 5 and G, so as to have no straight art of sneh length and 1Width as to be capale of receiving` one of the grinding bodies fz, the ehamfering oit of the side of each slot to give the necessary flare being continuons, but. the saine result may be secured, as shown at f2 in Fig. t, by making the slot straight and by ehamfering off the sides of the slot in saw-tooth notches f, the points ffglminnr v-separated longitudinally by a distance less than the length of a grinding body and laterally by a distance less than the diameter ot Various other modifications of the form of the slots will readily suggest themselves' 1n View of the foregoino and 1t 1s obvious that the invent-ion is not limited to any pan tieular form.

The invention has been thus l'ar described with relation to the mid-partition or transverse wall j between the t-Wo con'ipartn'ients but as the end partition or t fansvcrse Wall oi the discharme head c may also be formed with slots 'which flare toward the discharge end of the tnbeinill, such slots of such end wall. may also be formed as described with reiterenee to the niid Wall j and as shown in Figs. Z-t. Y bodies to lodge in the slots ol the end wall, which tlaro array from the eonipzlrtinent. 'is milch loss than 'in the (fase. ot the slots in. the n'ri ln:1ll. which tlaro tmvard tho conn partnirnt, lint should such lorhfingg occur the 'formation otl the slotsdcscribed will insure portion of the grinding' bodiesl they are lilirl)Y to be dislodged ding bodies within the rempart-- the ondw'm i'roin Whi by tli-r lifi-in nient.

l claim. as my invention:

l. The cornlnimt-ion with a 'tnbcniill and relatively small. o ,vlindrioal grinding bodies ot' a transverse wall havingv continuons slots longer than the c lindrical grinding bodies and 'termed with bearing; points separated by lts than thc length ot a. grindinnl` body, rslnnrfbx a grinding body cannot lodge in the slot with its .-ixis parallel with tho plane. ot the wall.

9. The combination with a tnlirinill and relatively small, evliinlriral grinding, bodies ot a transverse nall having continuons slots longer than the cylindrical grinding bodies and Haring;l toward the discharge end. of the tnbeinill and 'l'oiined with bearing-points separated by less than the length of a grinding body, whereby a grinding body cannot,- lodge in the Slot with its axis parallel with the plane ot the wall.

3. The conll'iination with a tnboniill and relatively small, cylindrical grinding bodies of' a transverse wall hai-'ing continnons slots `toi-ming' bearing points sepa-rated by less than the length of a. eylind rical body, whereby a grinding body cannot' lodge in the slot with its axis parallel With the plane 0f the Wall.

This specification signed and witnessed:

f this 3rd day of January, A. D. 1,910.

POVL T. LINDHARD.

Signed in the presence o C. J. IVIMEY, H. W. LoGAN.

'lh'e liability oi the grindingh 

